1. Field of the Invention
This invention relates to new and useful improvements in the manufacture of bearings and more particularly to processes for manufacturing diamond faced bearing assemblies.
2. Description of the Prior Art
It is well known to use diamond bits for earth drilling using natural or synthetic diamonds bonded to supporting metallic or carbide studs or slugs. There are several types of diamond bits known to the drilling industry. In one type, the diamonds are a very small size and randomly distributed in a supporting matrix. Another type contains diamonds of a larger size positioned on the surface of a drill shank in a predetermined pattern. Still another type involves the use of a cutter formed of a polycrystalline diamond supported on a sintered carbide support.
Some of the most recent publications dealing with diamond bits of advanced design are Rowley, et al. U.S. Pat. No. 4,073,354 and Rohde, et al. U.S. Pat. No. 4,098,363. An example of cutting inserts using polycrystalline diamond cutters and an illustration of a drill bit using such cutters, is found in Daniels, et al. U.S. Pat. No. 4,156,329.
The most comprehensive treatment of this subject in the literature is probably the chapter entitled STRATAPAX bits, pages 541-591 in ADVANCED DRILLING TECHNIQUES, by William C. Maurer, The Petroleum Publishing Company, 1421 South Sheridan Road, P.O. Box 1260, Tulsa, Okla., 74101, published in 1980. This reference illustrates and discusses in detail the development of the STRATAPAX diamond cutting elements by General Electric and gives several examples of commercial drill bits and prototypes using such cutting elements.
Polycrystalline diamond inserts have had extensive treatment in the literature as cutting elements for drill bits but there has been no suggestion of the use or application of diamond elements for friction bearings and particularly for bearings in turbodrills where the conditions of load and wear are severe.
In co-pending application, Ser. No. 306,290, filed Sept. 28, 1981, there is disclosed a turbodrill having longitudinal thrust bearings consisting of polycrystalline-diamond-faced carbide inserts used in combination with conventional radial bearings. The diamond bearing inserts are positioned in cylindrical recesses in an annular supporting plate or ring with the flat diamond faces lying substantially in a plane.
While the diamond bearing inserts are made with a high degree of dimensional precision, it has been difficult to drill holes or recesses in the supporting plate with sufficient precision to locate the bearing surfaces accurately in a single plane. This has resulted in minor variations in the amount of protrusion of the bearing inserts from the supporting plate which provides an irregular bearing surface. As a result, there has been a substantial need for a manufacturing technique which will produce a diamond bearing of this type with the bearing faces accurately located in a single plane.